Atlanta -LRB- CNN -RRB- -- Hussein Shafei prepared Saturday for a journey back to a place of darkness in Libya .

Soon , he plans to stand again in Cell 14 , Block 2 at the Abu Salim prison in Tripoli . Only this time , the metal door will not slam behind him , caging him in a bathroom-size cell .

He will be a free man within the confines of what became a potent symbol of Moammar Gadhafi 's repression -- Libya 's Abu Ghraib .

Shafei wants to return to the place where he witnessed a massacre that fuels his nightmares . Sometimes , he said , his wife would wake him up in the middle of the night , saying , `` Hussein . You are screaming . You are scaring the kids . ''

As many as 1,200 prisoners were killed at Abu Salim in the summer of 1996 , according to Human Rights Watch . Without justice , the infamous event festered in Libya 's national psyche and eventually acted as tinder to spark the flame of revolt in February of this year .

Rebels stormed the prison a few days ago , freeing those held inside , including an American journalist .

`` I am so excited about Tripoli , '' Shafei said of the distinct possibility of the capital falling under rebel control . `` This is the moment I have been waiting for for so many years . ''

Since his release in 2000 , Shafei had thought about Abu Salim 's dead . Where were their bodies ? What was it like for their children to grow up without their fathers ? For a wife to not know what happened to her husband ?

He vowed to expose the carnage of that June day .

Then this week in Benghazi , he watched a video posted on YouTube that purportedly showed the storming of Abu Salim . Shafei , now working with the opposition in Benghazi , knew he had to return there .

He was waiting to board a plane to Tripoli . Or perhaps , with the fighting still raging in places like Gadhafi 's hometown of Sirte , he will have to go by boat .

With the Libyan regime on the brink of collapse , Shafei hopes the truth about Abu Salim will finally be known . He is hardly alone in his wish .

The shooting went on for almost three hours

Shafei was a teenage college student when he was arrested for offending the regime . Inspired by perestroika reforms in the Soviet Union in the late 1980s , he spoke out in favor of greater freedoms in his own country .

Shafei 's mother , Najia , clearly remembers that day in 1988 when she returned to her home in Benghazi to find her daughters wailing . Her son was gone .

`` We had no idea where he was , '' she said from her home in Atlanta . `` Whether he was alive or dead . ''

Nineteen months passed before Najia Shafei learned , through contacts , her son 's whereabouts . After that , she occasionally made the long trek west from Benghazi to the prison in Tripoli .

The guards would drag her son out of his cell and into a warehouse at the entrance of the jail , where mother and son met .

If she was lucky , she got 20 minutes with him , she said .

She could never ask him about his situation . There were always guards listening in . He could never tell her about what he knew was going on in that jail -- beatings , torture , deaths .

Shafei spent eight years that way , in a cramped cell , without his family or the education he should have finished . His father died in 1994 and he was released for three days to attend the funeral . That was the extent of his freedom .

Then , on June 28 , 1996 , prisoners rioting over poor conditions and restricted family visits seized a guard and escaped from their cells .

`` Five or seven minutes after it started , the guards on the roofs shot at the prisoners who were in the open areas , '' Shafei said in an interview with Human Rights Watch many years later .

Security officials ordered the shooting to stop and feigned negotiations . But Shafei told Human Rights Watch that the officials instead called in firing squads to gun down about 1,200 people .

He said a grenade was thrown into the courtyards where the prisoners were gathered .

`` I heard an explosion , and right after , a constant shooting started from heavy weapons and Kalashnikovs from the top of the roofs , '' he said . `` The shooting continued from 11 until 1:35 . ''

Much later , while buying lamb at a slaughterhouse in the United States , Shafei commented to his brother Nabil : Not even here can they kill at the rate Gadhafi 's men did that day .

`` I could not see the dead prisoners who were shot , but I could see those who were shooting , '' Shafei told Human Rights Watch . `` They were a special unit and wearing khaki military hats . Six were using Kalashnikovs . I saw them -- at least six men -- on the roofs of the cellblocks . ''

The next day , Shafei was ordered to clean the blood-smeared watches taken off the wrists of the dead .

Human Rights Watch said it had no way to verify Shafei 's story but another description of the incident from a report by the opposition National Front for the Salvation of Libya corroborated Shafei 's account .

Gadhafi 's government did not acknowledge the killings and denied any crime had taken place . More than a decade after the Abu Salim incident , the United Nations Human Rights Council noted that the Libyan government was unable to provide any information on its investigation of the allegations .

But the families , mostly from Benghazi , now the de facto rebel capital , did not abandon their longing for answers .

Some of them filed a complaint in a Libyan court in 2007 . The Gadhafi regime offered them compensation in exchange for their silence , according to Human Rights Watch .

But the families refused the money , considering it a bribe . Instead , they boldly began to protest each Saturday in Benghazi , an action unprecedented in Gadhafi 's four decades of rule .

`` It was radical , '' said Sarah Leah Whitson , director of the Middle East and Africa division at Human Rights Watch .

The government began informing some of the families that their loved ones were dead . But no bodies was ever returned nor a cause of death given .

Among those waiting to find out more are three brothers in Atlanta whose father , opposition activist Izzat Almegaryaf , was plucked from his home 20 years ago .

The Almegaryaf brothers know their father was detained at Abu Salim -- they received letters from him in the early 1990s . But the letters stopped a few years into Izzat Almegaryaf 's imprisonment . His sons do not know whether their father was among the massacre victims .

Tasbeeh Herwees , a Libyan-American journalism student in California , recalled in a blog post the funerals for the Abu Salim victims held in the summer of 2009 when she visited Benghazi .

`` Inna lillahi wa ilayhi rajioon , '' each family said . Verily , we belong to God , and to God we return .

Herwees tripped over the words in Arabic , but by the end of her stay she had repeated the phrase so many times that she was fluent .

`` I spent more time in tents that summer than in my own home , the cloth of my black abaya sticking irritatingly to my skin from the Saharan humidity , '' she wrote . `` In the faces of the family of the dead , I detected relief in the sea of sadness . ` At least now we know , ' they said . ''

Then in February of this year , the regime arrested Fathi Terbil , a human rights lawyer who represented some of the Abu Salim families . Hundreds of people jammed the streets of Benghazi to protest .

Terbil was released but the demonstrations did not stop . A revolution took root .

`` The memories of that summer come rushing back as I watch the present events in Libya unfold from my home in Cypress , California , '' Herwees wrote . `` It was , after all , the Abu Salim families who kick-started this revolution . It was they who initiated protests in Benghazi in front of police headquarters when their lawyer , Fathi Terbil , was mysteriously detained by security officials . ''

Exposing the carnage

After 12 years at Abu Salim , Shafei was released in 2000 . He often cried openly , with flashbacks triggered by something as small as macaroni reminiscent of Abu Salim chow , said his older brother , Nabil Shafei .

He eventually made his way to the United States , where Nabil lived .

`` Hussein came here and had a mission , '' Nabil Shafei said . `` He wanted to expose the massacre of Abu Salim . ''

Hussein Shafei told Human Rights Watch about the carnage he witnessed . He even approached the State Department , which includes the Abu Salim massacre in its statements on human rights abuses in Libya .

As the civil war raged this year and Benghazi blossomed as a city free of Gadhafi 's grip , Shafei , now 42 , returned there from Charlotte , North Carolina . He took his wife and three children with him .

He has been working with the opposition television station and telling the world about the dark secrets of Abu Salim . Now , as the newly freed prisoners began returning home to Benghazi , Shafei knew the time had come for him to go back to the prison .

It is part of his own healing . The nation must heal , too , he believes . The first step will be to hold Libyan leaders accountable for what happened at the prison .

Najia Shafei is wary of her son 's trip to Tripoli . She remains fearful about what might happen to him as long as Gadhafi is still alive .

But Hussein Shafei is determined to complete his mission . He owes it to all those who survived Abu Salim . But mostly , he owes it to the souls of the dead .

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Hussein Shafei says he witnessed the 1996 killings of 1,200 prisoners at Abu Salim

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The Libyan government has never acknowledged a crime

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After his release , Shafei spoke to Human Rights Watch about the carnage

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The incident served as a trigger for the revolt against Moammar Gadhafi